High Blood Pressure (Hypertension): Causes, Treatment and Diet

Clinical content by Trevor Wing MBRCP FRCHM MBAcC BSc (Hons) MSc (Dist) DMed (Img). Last reviewed October 2026.

Key facts

High blood pressure often has no symptoms, so many people do not know they have it.
A reading above 140/90 is considered high blood pressure.
Untreated, it raises the risk of coronary artery disease, heart attack and stroke.
Diet, less salt, regular exercise and not smoking can all help lower it.
Never stop or change prescribed blood pressure medication without speaking to your doctor.

Overview

For something so common, it is remarkable how often high blood pressure goes undiagnosed. Left untreated, it can lead to some very serious, life-threatening conditions. Like many so-called lifestyle diseases, high blood pressure can often be controlled by making some simple changes to the way you live.

Causes of high blood pressure

Most people with undiagnosed high blood pressure have no idea they have it. The lack of symptoms does not mean it isn’t affecting your body. If it is not properly treated, it can cause very serious diseases, including coronary artery disease, heart attack and stroke.

Your blood pressure is a measure of the force your blood exerts on your blood vessels as it moves around your body. It is given as two numbers. Your systolic blood pressure measures the pressure as your heart pumps blood, and your diastolic blood pressure measures the pressure when your heart is at rest between beats. Blood pressure fluctuates during the day: it tends to be lower when you are resting or asleep and higher during activity, stress or excitement. Readings are written with the systolic number first, followed by the diastolic number (for example 120/80). Anything higher than 140/90 is considered high blood pressure.

Most high blood pressure has no identifiable cause and develops slowly over time. In some cases it develops because of another condition, such as alcohol misuse, kidney or adrenal gland problems, illegal drug use or sleep apnoea.

Anyone can develop high blood pressure, but certain things make it more likely:

Age (older people are more prone to it)
Ethnicity (it is more common in people of Black African or Black Caribbean heritage)
Stress
Smoking
Family history
Obesity
Too much salt (sodium) in the diet
Low vitamin D or potassium

Treatments for high blood pressure

Treatment varies. Some people respond well to simple diet and lifestyle changes, while others need medication to bring their blood pressure down to safe levels. Treatment options include:

Thiazide diuretics, which help your body get rid of excess water and salt, reducing your blood volume and lowering your blood pressure
Beta blockers, which slow your heart rate and reduce the force with which your heart pumps
ACE inhibitors, which help relax the walls of your blood vessels and may be particularly effective for people with kidney disease
Angiotensin II receptor blockers (ARBs), which block the action of a chemical that narrows your blood vessels
Calcium channel blockers, which relax the muscles around your blood vessels and are an effective treatment for older patients
Renin inhibitors, which slow your body’s production of renin, an enzyme made in the kidneys that can set off a chain reaction that raises blood pressure

Like all prescription medicines, these can have serious side effects. For that reason, it is worth trying to control your blood pressure through diet.

Superfoods that may help lower blood pressure

Hibiscus has long been used as a herbal remedy for high blood pressure. It acts as a natural diuretic and mimics some of the qualities of ACE inhibitors. It is widely available in herbal teas.
Coconut water is popular as a healthier alternative to sugary electrolyte drinks. It is naturally high in potassium and magnesium, which help regulate muscle function. Remember, your heart is a muscle!
Green tea is an antioxidant powerhouse that can lower blood pressure and LDL cholesterol and may help prevent heart attacks and strokes. Drink 2 to 3 cups a day.
Omega-3 is an essential fatty acid that can do wonders for high blood pressure. As well as lowering blood pressure, it decreases triglycerides and increases HDL (“good”) cholesterol.
Watermelon contains an amino acid called citrulline, which the body converts to L-arginine, an amino acid that helps control how hard your blood is pumped around your body.
Grapefruit is high in vitamin C, an antioxidant that can help prevent damage to blood vessels and lower LDL cholesterol. Warning: grapefruit and grapefruit juice interact with several blood pressure medicines, including some calcium channel blockers such as felodipine and amlodipine. If you take blood pressure medication, check with your doctor or pharmacist before eating grapefruit.
Apples are a great source of quercetin, a flavonoid with antioxidant properties that helps prevent free-radical damage, which may lead to hardening of the arteries.
Blueberries contain anthocyanins and proanthocyanidins, which mimic the action of ACE inhibitors and help relax the walls of your blood vessels.
Brazil nuts are a great source of selenium and magnesium, which work together to support heart health. Eating a handful of nuts (about 28g) a day is linked to around a 29% lower risk of coronary heart disease (Aune et al., BMC Medicine, 2016).
Broccoli is packed with phytoestrogens and vitamin C and can help lower cholesterol and blood pressure. Overcooked broccoli loses many of its nutrients, so eat it raw, lightly steamed or stir-fried.
Garlic contains allicin, which has been shown to lower blood pressure and LDL cholesterol and protect the heart. If garlic upsets your stomach, take garlic capsules instead.
Almonds are the best dietary source of vitamin E, an antioxidant that helps lower LDL cholesterol and strengthen the cardiovascular system.
Yoghurt contains probiotics that act as a natural ACE inhibitor and is high in calcium, magnesium and potassium, all necessary for a healthy cardiovascular system.
Bananas are naturally low in sodium and high in potassium. Potassium deficiency is a common cause of high blood pressure.
Cinnamon may lower blood pressure as well as cholesterol, according to some studies. It isn’t just for desserts: add it to coffee or savoury dishes too.

As well as adding these foods to your diet, reduce the salt in your diet by avoiding processed foods, and exercise regularly. If you do these things, you can get your blood pressure under control without the use of prescription medications. Never stop or change prescribed blood pressure medication without speaking to your doctor.

How can we help?

We offer naturopathic diet and lifestyle support for high blood pressure, working alongside your GP. If you take blood pressure medication, please continue it and tell us what you take, as some foods and herbs interact with these medicines.

Frequently asked questions

What blood pressure reading is too high?

Readings are written with the systolic number first and the diastolic number second, for example 120/80. Anything higher than 140/90 is considered high blood pressure.

Does high blood pressure cause symptoms?

Usually not. Most people with high blood pressure have no idea they have it, which is why regular checks matter.

Can diet lower blood pressure?

Yes, for many people. Reducing salt by avoiding processed foods, exercising regularly and eating foods rich in potassium, magnesium and antioxidants can help. Never stop or change prescribed medication without speaking to your doctor.

Is grapefruit safe with blood pressure medicines?

Not always. Grapefruit and grapefruit juice interact with several blood pressure medicines, including some calcium channel blockers such as felodipine and amlodipine. Check with your doctor or pharmacist first.

Book a consultation

To book, book an appointment online or call 020 3811 8778. Initial consultations last up to one hour at our clinic at 16 Bridle Lane, St Margaret’s, Twickenham TW1 3EE.

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